Spool for photographic films



1934- T. G. BAXENDEN ET AL 1,942,951

SPOOL FOR PHOTOGRAPHIC FILMS Filed Jan. 20, 1931 INVZIKIORS. T-G.BAXENDEN- .T.

RJIOLLYEAR- Patented Jan. 9, 1934 UNlTED STATES SPOOL FOR PHOTOGRAPHIC FILMS Thomas George Baxenden, Watford, and John Robert Collycar, Bushey, England Application January 20-, 1931, Serial No. 509,962, and in Great Britain February 11, 1930 1 Claim.

This invention relates to spools such as are used in roll-film cameras and more particularly to spools of this type which are made from sheet metal.

In the usual construction of such sheet metal spools the cylindrical core of the spool is made from a rectangular blank which is rolled up to form the core, the two edges of the blank which meet when it is rolled up being suitably turned over and shaped so as to produce a lipped slot, that is, one having its edges turned inwardly so as to form a guide for the end of the paper strip covering the film, which is passed through the slot in the well known manner. The blank is usually provided with a second shorter slot, so positioned that it comes diametrically opposite the first mentioned slot in the finished spool and end discs, secured to the core, are provided for guiding the film rolled thereon.

It has been found in spools constructed in this manner that, in consequence of the twisting action set-up during winding, particularly if the spool is at all tightly held in position, the lipped edges of the longer slot in the tubular core tend to move relatively to one another so that the slot is, in effect, out of alignment and the film is not correctly wound on the spool.

To overcome this disadvantage a spool of the above type is, according to the invention, provided with a slot having inturned edges which extend beyond the ends of the slot and are locked or secured together so as to prevent relative movement between the said edges. The inturned edges are preferably locked together by means of an outstanding corrugation on one edge which fits into an inpressed corrugation on the adjacent edge. Alternatively one of the inturned edges may be out so as to provide a short tongue which is bent round the other inturned edge or round a slot out therein, or the edges may both be turned over after the manner of the ordinary seamed joint as used in the manufacture of tin cans.

Preferred embodiments of the invention are shown in the accompanying drawing, wherein:-

Fig. 1 is a perspective view of a portion of a spool, the end discs being removed, showing one method of locking the inturned edges, while Fig. 2, is a similar view showing an alternative method of locking the edges.

The spool comprises a tubular body or core 5 provided with end discs (not shown) which are attached to the core in any suitable manner such as by welding or pressing. The body 5 is formed from a rectangular blank which is rolled up into cylindrical form, the edges which then meet being shaped so as to provide a longitudinal slot 6 these edges being also turned over so as to form inwardly projecting lips '7 which guide the end of the paper strip covering the film, when the 30 said end is inserted in the slot in the usual manner. These inturned edges or lips extend beyond the end of the slot 6 and in order to prevent relative movement between these edges they are locked together by means of an outstanding lug 5 or corrugation 8 (Fig. 1) on one edge which fits into an impressed corrugation 9 on the adjacent edge.

In an alternative construction (Fig. 2) one of the inturned edges is cut in such a manner as to 7 provide a short tongue 10 which is bent over so as to grip the oiher edge. A short slot 11, into which the tongue 10 fits, is provided in the other edge, although it will be clear that the tongue may project beyond the edge to which it is attached so that when it is bent over there is no necessity for the provision of slot 11.

In all the above constructions the corrugated or turned over portions may, if necessary, be secured by welding or soldering.

By the constructions above described the edges of the slot are held in their correct position and there is no tendency for the film to be badily wound on the spool due to distortion of the slot.

What we claim as our invention and desire to secure by Letters Patent is:--

A photographic film spool comprising a blank rolled in the form of a cylinder, the edges of the blank having inturned lips, said lips being spaced apart for a portion of the length of the cylinder providing a slot and interlocking distortions provided in the lips beyond the ends of the slot and securing the inturned edges together.

THOMAS GEORGE BAXENDEN. JOHN ROBERT COLLYEAR. 

